Fluid control devices include various categories of equipment with control valves and regulators. Such control devices are adapted to be coupled within a fluid process control system such as chemical treatment systems, natural gas delivery systems, etc., for controlling the flow of a fluid therethrough. Each control device includes a body defining a fluid flow-path and a control member assembly for adjusting a dimension of the flow-path. A seat ring is disposed within a throat of the valve body.
The control member assembly typically includes a valve plug assembly having a sealing disk with a sealing surface. When the outlet pressure of the valve body is high, a sealing surface of the sealing disk may sealingly engage the seat ring and close the throat. This prevents the flow of fluid through the regulator.
While the flow of fluid through the regulator is prevented when the sealing disk engages the seat ring, high pressure force from the fluid often still acts on any exposed external surfaces of the sealing disk. Such forces causes erosion and chunking, for example, of the sealing disk, as depicted on the sealing disks 10, 12, 14 and 16 of FIG. 1. As a result, the sealing disks of the conventional valve plug assemblies need to be serviced and/or replaced more often, reducing the service life and efficiency of the valve plug assembly and, ultimately, the fluid control device.